Examples

# URL shortener — the classic warm-up: a write path that mints keys, a read path that must be fast
actor    user     "User"
external browser  "Browser"

system shortener "URL shortener" {
  gateway   lb       "Load balancer"     { transit }
  service   api      "Shortener API"     tech Go
  service   keygen   "Key generator"     tech Go
  cache     redis    "Hot links"         tech Redis        owned_by api
  datastore urls     "Links DB"          tech PostgreSQL   owned_by api
  job       cleaner  "Expiry sweeper"    tech Go

  api     calls  keygen  over gRPC   "next unique key"
  api     reads  redis   over RESP   "302 fast path"
  api     reads  urls    over SQL    "cache miss"
  api     writes urls    over SQL    "new link"
  api     writes redis   over RESP   "warm the cache"
  cleaner writes urls    over SQL    "drop expired"
}

user calls shortener.api over HTTPS via shortener.lb "shorten · redirect"

env prod "Production" {
  cluster k8s "Kubernetes" nodes 3 cpu 8 mem 32Gi {
    run shortener.api    replicas 4 cpu 0.5 mem 512Mi
    run shortener.keygen replicas 2 cpu 0.25 mem 256Mi
    run shortener.cleaner replicas 1
  }
  managed cache_svc "Managed Redis"    { run shortener.redis }
  managed pg        "Managed Postgres" { run shortener.urls }
}

archcode: "0.2"
objects:
  - id: user
    kind: actor
    name: User
  - id: browser
    kind: external
    name: Browser
  - id: shortener
    kind: system
    name: "URL shortener"
  - id: shortener.lb
    kind: gateway
    name: "Load balancer"
    parent: shortener
    attrs:
      transit: []
  - id: shortener.api
    kind: service
    name: "Shortener API"
    parent: shortener
    attrs:
      tech: [Go]
  - id: shortener.keygen
    kind: service
    name: "Key generator"
    parent: shortener
    attrs:
      tech: [Go]
  - id: shortener.redis
    kind: cache
    name: "Hot links"
    parent: shortener
    attrs:
      tech: [Redis]
      owned_by: [api]
  - id: shortener.urls
    kind: datastore
    name: "Links DB"
    parent: shortener
    attrs:
      tech: [PostgreSQL]
      owned_by: [api]
  - id: shortener.cleaner
    kind: job
    name: "Expiry sweeper"
    parent: shortener
    attrs:
      tech: [Go]
  - id: prod
    kind: env
    name: Production
  - id: prod.k8s
    kind: cluster
    name: Kubernetes
    parent: prod
    attrs:
      nodes: ["3"]
      cpu: ["8"]
      mem: [32Gi]
  - id: prod.cache_svc
    kind: managed
    name: "Managed Redis"
    parent: prod
  - id: prod.pg
    kind: managed
    name: "Managed Postgres"
    parent: prod
relations:
  - from: api
    verb: calls
    to: keygen
    over: gRPC
    label: "next unique key"
  - from: api
    verb: reads
    to: redis
    over: RESP
    label: "302 fast path"
  - from: api
    verb: reads
    to: urls
    over: SQL
    label: "cache miss"
  - from: api
    verb: writes
    to: urls
    over: SQL
    label: "new link"
  - from: api
    verb: writes
    to: redis
    over: RESP
    label: "warm the cache"
  - from: cleaner
    verb: writes
    to: urls
    over: SQL
    label: "drop expired"
  - from: user
    verb: calls
    to: shortener.api
    over: HTTPS
    via: [shortener.lb]
    label: "shorten · redirect"
placements:
  - host: prod.k8s
    run: shortener.api
    attrs:
      replicas: ["4"]
      cpu: ["0.5"]
      mem: [512Mi]
  - host: prod.k8s
    run: shortener.keygen
    attrs:
      replicas: ["2"]
      cpu: ["0.25"]
      mem: [256Mi]
  - host: prod.k8s
    run: shortener.cleaner
    attrs:
      replicas: ["1"]
  - host: prod.cache_svc
    run: shortener.redis
  - host: prod.pg
    run: shortener.urls

{
  "archcode": "0.2",
  "objects": [
    {
      "id": "user",
      "kind": "actor",
      "name": "User"
    },
    {
      "id": "browser",
      "kind": "external",
      "name": "Browser"
    },
    {
      "id": "shortener",
      "kind": "system",
      "name": "URL shortener"
    },
    {
      "id": "shortener.lb",
      "kind": "gateway",
      "name": "Load balancer",
      "parent": "shortener",
      "attrs": {
        "transit": []
      }
    },
    {
      "id": "shortener.api",
      "kind": "service",
      "name": "Shortener API",
      "parent": "shortener",
      "attrs": {
        "tech": [
          "Go"
        ]
      }
    },
    {
      "id": "shortener.keygen",
      "kind": "service",
      "name": "Key generator",
      "parent": "shortener",
      "attrs": {
        "tech": [
          "Go"
        ]
      }
    },
    {
      "id": "shortener.redis",
      "kind": "cache",
      "name": "Hot links",
      "parent": "shortener",
      "attrs": {
        "tech": [
          "Redis"
        ],
        "owned_by": [
          "api"
        ]
      }
    },
    {
      "id": "shortener.urls",
      "kind": "datastore",
      "name": "Links DB",
      "parent": "shortener",
      "attrs": {
        "tech": [
          "PostgreSQL"
        ],
        "owned_by": [
          "api"
        ]
      }
    },
    {
      "id": "shortener.cleaner",
      "kind": "job",
      "name": "Expiry sweeper",
      "parent": "shortener",
      "attrs": {
        "tech": [
          "Go"
        ]
      }
    },
    {
      "id": "prod",
      "kind": "env",
      "name": "Production"
    },
    {
      "id": "prod.k8s",
      "kind": "cluster",
      "name": "Kubernetes",
      "parent": "prod",
      "attrs": {
        "nodes": [
          "3"
        ],
        "cpu": [
          "8"
        ],
        "mem": [
          "32Gi"
        ]
      }
    },
    {
      "id": "prod.cache_svc",
      "kind": "managed",
      "name": "Managed Redis",
      "parent": "prod"
    },
    {
      "id": "prod.pg",
      "kind": "managed",
      "name": "Managed Postgres",
      "parent": "prod"
    }
  ],
  "relations": [
    {
      "from": "api",
      "verb": "calls",
      "to": "keygen",
      "over": "gRPC",
      "label": "next unique key"
    },
    {
      "from": "api",
      "verb": "reads",
      "to": "redis",
      "over": "RESP",
      "label": "302 fast path"
    },
    {
      "from": "api",
      "verb": "reads",
      "to": "urls",
      "over": "SQL",
      "label": "cache miss"
    },
    {
      "from": "api",
      "verb": "writes",
      "to": "urls",
      "over": "SQL",
      "label": "new link"
    },
    {
      "from": "api",
      "verb": "writes",
      "to": "redis",
      "over": "RESP",
      "label": "warm the cache"
    },
    {
      "from": "cleaner",
      "verb": "writes",
      "to": "urls",
      "over": "SQL",
      "label": "drop expired"
    },
    {
      "from": "user",
      "verb": "calls",
      "to": "shortener.api",
      "over": "HTTPS",
      "via": [
        "shortener.lb"
      ],
      "label": "shorten · redirect"
    }
  ],
  "placements": [
    {
      "host": "prod.k8s",
      "run": "shortener.api",
      "attrs": {
        "replicas": [
          "4"
        ],
        "cpu": [
          "0.5"
        ],
        "mem": [
          "512Mi"
        ]
      }
    },
    {
      "host": "prod.k8s",
      "run": "shortener.keygen",
      "attrs": {
        "replicas": [
          "2"
        ],
        "cpu": [
          "0.25"
        ],
        "mem": [
          "256Mi"
        ]
      }
    },
    {
      "host": "prod.k8s",
      "run": "shortener.cleaner",
      "attrs": {
        "replicas": [
          "1"
        ]
      }
    },
    {
      "host": "prod.cache_svc",
      "run": "shortener.redis"
    },
    {
      "host": "prod.pg",
      "run": "shortener.urls"
    }
  ]
}

# Rate limiter — a gateway that says no politely, with counters in a shared cache and rules in a store
actor    client   "API client"

system edge "API edge" {
  gateway   gw        "API gateway"        { transit  tech Envoy }
  service   limiter   "Rate limiter"       tech Go     "token bucket per key"
  cache     counters  "Counters"           tech Redis  owned_by limiter
  datastore rules     "Rules"              tech etcd   owned_by limiter
  service   backend   "Protected service"  tech Kotlin

  limiter reads  counters over RESP  "take a token"
  limiter writes counters over RESP  "refill"
  limiter reads  rules    over gRPC  "limits per client, cached 30s"
}

client calls edge.limiter over HTTPS via edge.gw "every request"
edge.limiter calls edge.backend over HTTP "allowed"

env prod "Production" {
  cluster k8s "Kubernetes" nodes 4 cpu 8 mem 32Gi {
    run edge.limiter replicas 6 cpu 0.5 mem 256Mi
    run edge.backend replicas 3 cpu 1   mem 1Gi
  }
  managed redis_svc "Managed Redis" { run edge.counters }
  node    etcd1 "etcd" count 3 cpu 2 mem 4Gi { run edge.rules }
}

archcode: "0.2"
objects:
  - id: client
    kind: actor
    name: "API client"
  - id: edge
    kind: system
    name: "API edge"
  - id: edge.gw
    kind: gateway
    name: "API gateway"
    parent: edge
    attrs:
      transit: []
      tech: [Envoy]
  - id: edge.limiter
    kind: service
    name: "Rate limiter"
    parent: edge
    attrs:
      tech: [Go, "token bucket per key"]
  - id: edge.counters
    kind: cache
    name: Counters
    parent: edge
    attrs:
      tech: [Redis]
      owned_by: [limiter]
  - id: edge.rules
    kind: datastore
    name: Rules
    parent: edge
    attrs:
      tech: [etcd]
      owned_by: [limiter]
  - id: edge.backend
    kind: service
    name: "Protected service"
    parent: edge
    attrs:
      tech: [Kotlin]
  - id: prod
    kind: env
    name: Production
  - id: prod.k8s
    kind: cluster
    name: Kubernetes
    parent: prod
    attrs:
      nodes: ["4"]
      cpu: ["8"]
      mem: [32Gi]
  - id: prod.redis_svc
    kind: managed
    name: "Managed Redis"
    parent: prod
  - id: prod.etcd1
    kind: node
    name: etcd
    parent: prod
    attrs:
      count: ["3"]
      cpu: ["2"]
      mem: [4Gi]
relations:
  - from: limiter
    verb: reads
    to: counters
    over: RESP
    label: "take a token"
  - from: limiter
    verb: writes
    to: counters
    over: RESP
    label: refill
  - from: limiter
    verb: reads
    to: rules
    over: gRPC
    label: "limits per client, cached 30s"
  - from: client
    verb: calls
    to: edge.limiter
    over: HTTPS
    via: [edge.gw]
    label: "every request"
  - from: edge.limiter
    verb: calls
    to: edge.backend
    over: HTTP
    label: allowed
placements:
  - host: prod.k8s
    run: edge.limiter
    attrs:
      replicas: ["6"]
      cpu: ["0.5"]
      mem: [256Mi]
  - host: prod.k8s
    run: edge.backend
    attrs:
      replicas: ["3"]
      cpu: ["1"]
      mem: [1Gi]
  - host: prod.redis_svc
    run: edge.counters
  - host: prod.etcd1
    run: edge.rules

{
  "archcode": "0.2",
  "objects": [
    {
      "id": "client",
      "kind": "actor",
      "name": "API client"
    },
    {
      "id": "edge",
      "kind": "system",
      "name": "API edge"
    },
    {
      "id": "edge.gw",
      "kind": "gateway",
      "name": "API gateway",
      "parent": "edge",
      "attrs": {
        "transit": [],
        "tech": [
          "Envoy"
        ]
      }
    },
    {
      "id": "edge.limiter",
      "kind": "service",
      "name": "Rate limiter",
      "parent": "edge",
      "attrs": {
        "tech": [
          "Go",
          "token bucket per key"
        ]
      }
    },
    {
      "id": "edge.counters",
      "kind": "cache",
      "name": "Counters",
      "parent": "edge",
      "attrs": {
        "tech": [
          "Redis"
        ],
        "owned_by": [
          "limiter"
        ]
      }
    },
    {
      "id": "edge.rules",
      "kind": "datastore",
      "name": "Rules",
      "parent": "edge",
      "attrs": {
        "tech": [
          "etcd"
        ],
        "owned_by": [
          "limiter"
        ]
      }
    },
    {
      "id": "edge.backend",
      "kind": "service",
      "name": "Protected service",
      "parent": "edge",
      "attrs": {
        "tech": [
          "Kotlin"
        ]
      }
    },
    {
      "id": "prod",
      "kind": "env",
      "name": "Production"
    },
    {
      "id": "prod.k8s",
      "kind": "cluster",
      "name": "Kubernetes",
      "parent": "prod",
      "attrs": {
        "nodes": [
          "4"
        ],
        "cpu": [
          "8"
        ],
        "mem": [
          "32Gi"
        ]
      }
    },
    {
      "id": "prod.redis_svc",
      "kind": "managed",
      "name": "Managed Redis",
      "parent": "prod"
    },
    {
      "id": "prod.etcd1",
      "kind": "node",
      "name": "etcd",
      "parent": "prod",
      "attrs": {
        "count": [
          "3"
        ],
        "cpu": [
          "2"
        ],
        "mem": [
          "4Gi"
        ]
      }
    }
  ],
  "relations": [
    {
      "from": "limiter",
      "verb": "reads",
      "to": "counters",
      "over": "RESP",
      "label": "take a token"
    },
    {
      "from": "limiter",
      "verb": "writes",
      "to": "counters",
      "over": "RESP",
      "label": "refill"
    },
    {
      "from": "limiter",
      "verb": "reads",
      "to": "rules",
      "over": "gRPC",
      "label": "limits per client, cached 30s"
    },
    {
      "from": "client",
      "verb": "calls",
      "to": "edge.limiter",
      "over": "HTTPS",
      "via": [
        "edge.gw"
      ],
      "label": "every request"
    },
    {
      "from": "edge.limiter",
      "verb": "calls",
      "to": "edge.backend",
      "over": "HTTP",
      "label": "allowed"
    }
  ],
  "placements": [
    {
      "host": "prod.k8s",
      "run": "edge.limiter",
      "attrs": {
        "replicas": [
          "6"
        ],
        "cpu": [
          "0.5"
        ],
        "mem": [
          "256Mi"
        ]
      }
    },
    {
      "host": "prod.k8s",
      "run": "edge.backend",
      "attrs": {
        "replicas": [
          "3"
        ],
        "cpu": [
          "1"
        ],
        "mem": [
          "1Gi"
        ]
      }
    },
    {
      "host": "prod.redis_svc",
      "run": "edge.counters"
    },
    {
      "host": "prod.etcd1",
      "run": "edge.rules"
    }
  ]
}

# News feed — fan-out on write: a post lands in every follower's feed cache before they ask
actor    member   "Member"

system feed "News feed" {
  gateway   gw        "API gateway"      { transit }
  service   posts     "Post service"     tech Java
  service   fanout    "Fan-out worker"   tech Java
  service   social    "Social graph"     tech Go
  service   timeline  "Feed service"     tech Java
  broker    events    "Post events"      { transit  tech Kafka }
  topic     post.created
  cache     feeds     "Feed cache"       tech Redis      owned_by timeline
  datastore post_db   "Posts"            tech Cassandra  owned_by posts
  datastore media     "Media"            tech S3         owned_by posts

  posts    writes     post_db  over CQL
  posts    writes     media    over HTTPS   "images, video"
  posts    publishes  post.created via events
  fanout   subscribes post.created via events
  fanout   calls      social   over gRPC    "followers of the author"
  fanout   writes     feeds    over RESP    "push the post id into each follower's list"
  timeline reads      feeds    over RESP
  timeline reads      post_db  over CQL     "hydrate the ids"
}

member calls feed.posts    over HTTPS via feed.gw "publish"
member calls feed.timeline over HTTPS via feed.gw "read the feed"

archcode: "0.2"
objects:
  - id: member
    kind: actor
    name: Member
  - id: feed
    kind: system
    name: "News feed"
  - id: feed.gw
    kind: gateway
    name: "API gateway"
    parent: feed
    attrs:
      transit: []
  - id: feed.posts
    kind: service
    name: "Post service"
    parent: feed
    attrs:
      tech: [Java]
  - id: feed.fanout
    kind: service
    name: "Fan-out worker"
    parent: feed
    attrs:
      tech: [Java]
  - id: feed.social
    kind: service
    name: "Social graph"
    parent: feed
    attrs:
      tech: [Go]
  - id: feed.timeline
    kind: service
    name: "Feed service"
    parent: feed
    attrs:
      tech: [Java]
  - id: feed.events
    kind: broker
    name: "Post events"
    parent: feed
    attrs:
      transit: []
      tech: [Kafka]
  - id: post.created
    kind: topic
    parent: feed
  - id: feed.feeds
    kind: cache
    name: "Feed cache"
    parent: feed
    attrs:
      tech: [Redis]
      owned_by: [timeline]
  - id: feed.post_db
    kind: datastore
    name: Posts
    parent: feed
    attrs:
      tech: [Cassandra]
      owned_by: [posts]
  - id: feed.media
    kind: datastore
    name: Media
    parent: feed
    attrs:
      tech: [S3]
      owned_by: [posts]
relations:
  - from: posts
    verb: writes
    to: post_db
    over: CQL
  - from: posts
    verb: writes
    to: media
    over: HTTPS
    label: "images, video"
  - from: posts
    verb: publishes
    to: post.created
    via: [events]
  - from: fanout
    verb: subscribes
    to: post.created
    via: [events]
  - from: fanout
    verb: calls
    to: social
    over: gRPC
    label: "followers of the author"
  - from: fanout
    verb: writes
    to: feeds
    over: RESP
    label: "push the post id into each follower's list"
  - from: timeline
    verb: reads
    to: feeds
    over: RESP
  - from: timeline
    verb: reads
    to: post_db
    over: CQL
    label: "hydrate the ids"
  - from: member
    verb: calls
    to: feed.posts
    over: HTTPS
    via: [feed.gw]
    label: publish
  - from: member
    verb: calls
    to: feed.timeline
    over: HTTPS
    via: [feed.gw]
    label: "read the feed"
placements: []

{
  "archcode": "0.2",
  "objects": [
    {
      "id": "member",
      "kind": "actor",
      "name": "Member"
    },
    {
      "id": "feed",
      "kind": "system",
      "name": "News feed"
    },
    {
      "id": "feed.gw",
      "kind": "gateway",
      "name": "API gateway",
      "parent": "feed",
      "attrs": {
        "transit": []
      }
    },
    {
      "id": "feed.posts",
      "kind": "service",
      "name": "Post service",
      "parent": "feed",
      "attrs": {
        "tech": [
          "Java"
        ]
      }
    },
    {
      "id": "feed.fanout",
      "kind": "service",
      "name": "Fan-out worker",
      "parent": "feed",
      "attrs": {
        "tech": [
          "Java"
        ]
      }
    },
    {
      "id": "feed.social",
      "kind": "service",
      "name": "Social graph",
      "parent": "feed",
      "attrs": {
        "tech": [
          "Go"
        ]
      }
    },
    {
      "id": "feed.timeline",
      "kind": "service",
      "name": "Feed service",
      "parent": "feed",
      "attrs": {
        "tech": [
          "Java"
        ]
      }
    },
    {
      "id": "feed.events",
      "kind": "broker",
      "name": "Post events",
      "parent": "feed",
      "attrs": {
        "transit": [],
        "tech": [
          "Kafka"
        ]
      }
    },
    {
      "id": "post.created",
      "kind": "topic",
      "parent": "feed"
    },
    {
      "id": "feed.feeds",
      "kind": "cache",
      "name": "Feed cache",
      "parent": "feed",
      "attrs": {
        "tech": [
          "Redis"
        ],
        "owned_by": [
          "timeline"
        ]
      }
    },
    {
      "id": "feed.post_db",
      "kind": "datastore",
      "name": "Posts",
      "parent": "feed",
      "attrs": {
        "tech": [
          "Cassandra"
        ],
        "owned_by": [
          "posts"
        ]
      }
    },
    {
      "id": "feed.media",
      "kind": "datastore",
      "name": "Media",
      "parent": "feed",
      "attrs": {
        "tech": [
          "S3"
        ],
        "owned_by": [
          "posts"
        ]
      }
    }
  ],
  "relations": [
    {
      "from": "posts",
      "verb": "writes",
      "to": "post_db",
      "over": "CQL"
    },
    {
      "from": "posts",
      "verb": "writes",
      "to": "media",
      "over": "HTTPS",
      "label": "images, video"
    },
    {
      "from": "posts",
      "verb": "publishes",
      "to": "post.created",
      "via": [
        "events"
      ]
    },
    {
      "from": "fanout",
      "verb": "subscribes",
      "to": "post.created",
      "via": [
        "events"
      ]
    },
    {
      "from": "fanout",
      "verb": "calls",
      "to": "social",
      "over": "gRPC",
      "label": "followers of the author"
    },
    {
      "from": "fanout",
      "verb": "writes",
      "to": "feeds",
      "over": "RESP",
      "label": "push the post id into each follower's list"
    },
    {
      "from": "timeline",
      "verb": "reads",
      "to": "feeds",
      "over": "RESP"
    },
    {
      "from": "timeline",
      "verb": "reads",
      "to": "post_db",
      "over": "CQL",
      "label": "hydrate the ids"
    },
    {
      "from": "member",
      "verb": "calls",
      "to": "feed.posts",
      "over": "HTTPS",
      "via": [
        "feed.gw"
      ],
      "label": "publish"
    },
    {
      "from": "member",
      "verb": "calls",
      "to": "feed.timeline",
      "over": "HTTPS",
      "via": [
        "feed.gw"
      ],
      "label": "read the feed"
    }
  ],
  "placements": []
}

# Chat — long-lived connections in front, a message log behind, presence on the side
actor    person   "Person"

system chat "Chat" {
  gateway   ws        "WebSocket gateway"  { transit  tech Go }
  service   messages  "Message service"    tech Elixir
  service   presence  "Presence"           tech Elixir
  service   push      "Push relay"         tech Go
  broker    bus       "Message bus"        { transit  tech NATS }
  topic     message.sent
  datastore log       "Message log"        tech ScyllaDB  owned_by messages
  cache     online    "Who is online"      tech Redis     owned_by presence

  messages  writes     log      over CQL
  messages  publishes  message.sent via bus
  push      subscribes message.sent via bus   "recipient offline → notify"
  presence  writes     online   over RESP     "heartbeats with a TTL"
  messages  reads      online   over RESP     "deliver now or queue"
}

external apns "Apple Push"   { stage live }
external fcm  "Google Push"  { stage live }

person       calls chat.messages over WSS via chat.ws "send · receive"
person       calls chat.presence over WSS via chat.ws "heartbeat"
chat.push    calls apns over HTTPS
chat.push    calls fcm  over HTTPS

archcode: "0.2"
objects:
  - id: person
    kind: actor
    name: Person
  - id: chat
    kind: system
    name: Chat
  - id: chat.ws
    kind: gateway
    name: "WebSocket gateway"
    parent: chat
    attrs:
      transit: []
      tech: [Go]
  - id: chat.messages
    kind: service
    name: "Message service"
    parent: chat
    attrs:
      tech: [Elixir]
  - id: chat.presence
    kind: service
    name: Presence
    parent: chat
    attrs:
      tech: [Elixir]
  - id: chat.push
    kind: service
    name: "Push relay"
    parent: chat
    attrs:
      tech: [Go]
  - id: chat.bus
    kind: broker
    name: "Message bus"
    parent: chat
    attrs:
      transit: []
      tech: [NATS]
  - id: message.sent
    kind: topic
    parent: chat
  - id: chat.log
    kind: datastore
    name: "Message log"
    parent: chat
    attrs:
      tech: [ScyllaDB]
      owned_by: [messages]
  - id: chat.online
    kind: cache
    name: "Who is online"
    parent: chat
    attrs:
      tech: [Redis]
      owned_by: [presence]
  - id: apns
    kind: external
    name: "Apple Push"
    attrs:
      stage: [live]
  - id: fcm
    kind: external
    name: "Google Push"
    attrs:
      stage: [live]
relations:
  - from: messages
    verb: writes
    to: log
    over: CQL
  - from: messages
    verb: publishes
    to: message.sent
    via: [bus]
  - from: push
    verb: subscribes
    to: message.sent
    via: [bus]
    label: "recipient offline → notify"
  - from: presence
    verb: writes
    to: online
    over: RESP
    label: "heartbeats with a TTL"
  - from: messages
    verb: reads
    to: online
    over: RESP
    label: "deliver now or queue"
  - from: person
    verb: calls
    to: chat.messages
    over: WSS
    via: [chat.ws]
    label: "send · receive"
  - from: person
    verb: calls
    to: chat.presence
    over: WSS
    via: [chat.ws]
    label: heartbeat
  - from: chat.push
    verb: calls
    to: apns
    over: HTTPS
  - from: chat.push
    verb: calls
    to: fcm
    over: HTTPS
placements: []

{
  "archcode": "0.2",
  "objects": [
    {
      "id": "person",
      "kind": "actor",
      "name": "Person"
    },
    {
      "id": "chat",
      "kind": "system",
      "name": "Chat"
    },
    {
      "id": "chat.ws",
      "kind": "gateway",
      "name": "WebSocket gateway",
      "parent": "chat",
      "attrs": {
        "transit": [],
        "tech": [
          "Go"
        ]
      }
    },
    {
      "id": "chat.messages",
      "kind": "service",
      "name": "Message service",
      "parent": "chat",
      "attrs": {
        "tech": [
          "Elixir"
        ]
      }
    },
    {
      "id": "chat.presence",
      "kind": "service",
      "name": "Presence",
      "parent": "chat",
      "attrs": {
        "tech": [
          "Elixir"
        ]
      }
    },
    {
      "id": "chat.push",
      "kind": "service",
      "name": "Push relay",
      "parent": "chat",
      "attrs": {
        "tech": [
          "Go"
        ]
      }
    },
    {
      "id": "chat.bus",
      "kind": "broker",
      "name": "Message bus",
      "parent": "chat",
      "attrs": {
        "transit": [],
        "tech": [
          "NATS"
        ]
      }
    },
    {
      "id": "message.sent",
      "kind": "topic",
      "parent": "chat"
    },
    {
      "id": "chat.log",
      "kind": "datastore",
      "name": "Message log",
      "parent": "chat",
      "attrs": {
        "tech": [
          "ScyllaDB"
        ],
        "owned_by": [
          "messages"
        ]
      }
    },
    {
      "id": "chat.online",
      "kind": "cache",
      "name": "Who is online",
      "parent": "chat",
      "attrs": {
        "tech": [
          "Redis"
        ],
        "owned_by": [
          "presence"
        ]
      }
    },
    {
      "id": "apns",
      "kind": "external",
      "name": "Apple Push",
      "attrs": {
        "stage": [
          "live"
        ]
      }
    },
    {
      "id": "fcm",
      "kind": "external",
      "name": "Google Push",
      "attrs": {
        "stage": [
          "live"
        ]
      }
    }
  ],
  "relations": [
    {
      "from": "messages",
      "verb": "writes",
      "to": "log",
      "over": "CQL"
    },
    {
      "from": "messages",
      "verb": "publishes",
      "to": "message.sent",
      "via": [
        "bus"
      ]
    },
    {
      "from": "push",
      "verb": "subscribes",
      "to": "message.sent",
      "via": [
        "bus"
      ],
      "label": "recipient offline → notify"
    },
    {
      "from": "presence",
      "verb": "writes",
      "to": "online",
      "over": "RESP",
      "label": "heartbeats with a TTL"
    },
    {
      "from": "messages",
      "verb": "reads",
      "to": "online",
      "over": "RESP",
      "label": "deliver now or queue"
    },
    {
      "from": "person",
      "verb": "calls",
      "to": "chat.messages",
      "over": "WSS",
      "via": [
        "chat.ws"
      ],
      "label": "send · receive"
    },
    {
      "from": "person",
      "verb": "calls",
      "to": "chat.presence",
      "over": "WSS",
      "via": [
        "chat.ws"
      ],
      "label": "heartbeat"
    },
    {
      "from": "chat.push",
      "verb": "calls",
      "to": "apns",
      "over": "HTTPS"
    },
    {
      "from": "chat.push",
      "verb": "calls",
      "to": "fcm",
      "over": "HTTPS"
    }
  ],
  "placements": []
}

# Notification system — one API in, three channels out, every provider behind a worker of its own
system notify "Notifications" {
  service   api        "Notification API"   tech Python
  broker    queue      "Channel queues"     { transit  tech RabbitMQ }
  topic     send.email
  topic     send.sms
  topic     send.push
  service   email_wrk  "Email worker"       tech Python
  service   sms_wrk    "SMS worker"         tech Python
  service   push_wrk   "Push worker"        tech Python
  datastore templates  "Templates"          tech PostgreSQL  owned_by api
  datastore prefs      "User preferences"   tech PostgreSQL  owned_by api
  datastore sent       "Delivery log"       tech ClickHouse

  api       reads      prefs      over SQL   "opt-outs, quiet hours"
  api       reads      templates  over SQL
  api       publishes  send.email via queue
  api       publishes  send.sms   via queue
  api       publishes  send.push  via queue
  email_wrk subscribes send.email via queue
  sms_wrk   subscribes send.sms   via queue
  push_wrk  subscribes send.push  via queue
  email_wrk writes sent over HTTP
  sms_wrk   writes sent over HTTP
  push_wrk  writes sent over HTTP
}

external orders   "Orders service"   description "an internal caller"
external mailer   "Email provider"
external smsgw    "SMS gateway"
external pushgw   "Push service"

orders           calls notify.api over HTTPS "send(user, template, data)"
notify.email_wrk calls mailer over HTTPS
notify.sms_wrk   calls smsgw  over HTTPS
notify.push_wrk  calls pushgw over HTTPS

archcode: "0.2"
objects:
  - id: notify
    kind: system
    name: Notifications
  - id: notify.api
    kind: service
    name: "Notification API"
    parent: notify
    attrs:
      tech: [Python]
  - id: notify.queue
    kind: broker
    name: "Channel queues"
    parent: notify
    attrs:
      transit: []
      tech: [RabbitMQ]
  - id: send.email
    kind: topic
    parent: notify
  - id: send.sms
    kind: topic
    parent: notify
  - id: send.push
    kind: topic
    parent: notify
  - id: notify.email_wrk
    kind: service
    name: "Email worker"
    parent: notify
    attrs:
      tech: [Python]
  - id: notify.sms_wrk
    kind: service
    name: "SMS worker"
    parent: notify
    attrs:
      tech: [Python]
  - id: notify.push_wrk
    kind: service
    name: "Push worker"
    parent: notify
    attrs:
      tech: [Python]
  - id: notify.templates
    kind: datastore
    name: Templates
    parent: notify
    attrs:
      tech: [PostgreSQL]
      owned_by: [api]
  - id: notify.prefs
    kind: datastore
    name: "User preferences"
    parent: notify
    attrs:
      tech: [PostgreSQL]
      owned_by: [api]
  - id: notify.sent
    kind: datastore
    name: "Delivery log"
    parent: notify
    attrs:
      tech: [ClickHouse]
  - id: orders
    kind: external
    name: "Orders service"
    attrs:
      description: ["an internal caller"]
  - id: mailer
    kind: external
    name: "Email provider"
  - id: smsgw
    kind: external
    name: "SMS gateway"
  - id: pushgw
    kind: external
    name: "Push service"
relations:
  - from: api
    verb: reads
    to: prefs
    over: SQL
    label: "opt-outs, quiet hours"
  - from: api
    verb: reads
    to: templates
    over: SQL
  - from: api
    verb: publishes
    to: send.email
    via: [queue]
  - from: api
    verb: publishes
    to: send.sms
    via: [queue]
  - from: api
    verb: publishes
    to: send.push
    via: [queue]
  - from: email_wrk
    verb: subscribes
    to: send.email
    via: [queue]
  - from: sms_wrk
    verb: subscribes
    to: send.sms
    via: [queue]
  - from: push_wrk
    verb: subscribes
    to: send.push
    via: [queue]
  - from: email_wrk
    verb: writes
    to: sent
    over: HTTP
  - from: sms_wrk
    verb: writes
    to: sent
    over: HTTP
  - from: push_wrk
    verb: writes
    to: sent
    over: HTTP
  - from: orders
    verb: calls
    to: notify.api
    over: HTTPS
    label: "send(user, template, data)"
  - from: notify.email_wrk
    verb: calls
    to: mailer
    over: HTTPS
  - from: notify.sms_wrk
    verb: calls
    to: smsgw
    over: HTTPS
  - from: notify.push_wrk
    verb: calls
    to: pushgw
    over: HTTPS
placements: []

{
  "archcode": "0.2",
  "objects": [
    {
      "id": "notify",
      "kind": "system",
      "name": "Notifications"
    },
    {
      "id": "notify.api",
      "kind": "service",
      "name": "Notification API",
      "parent": "notify",
      "attrs": {
        "tech": [
          "Python"
        ]
      }
    },
    {
      "id": "notify.queue",
      "kind": "broker",
      "name": "Channel queues",
      "parent": "notify",
      "attrs": {
        "transit": [],
        "tech": [
          "RabbitMQ"
        ]
      }
    },
    {
      "id": "send.email",
      "kind": "topic",
      "parent": "notify"
    },
    {
      "id": "send.sms",
      "kind": "topic",
      "parent": "notify"
    },
    {
      "id": "send.push",
      "kind": "topic",
      "parent": "notify"
    },
    {
      "id": "notify.email_wrk",
      "kind": "service",
      "name": "Email worker",
      "parent": "notify",
      "attrs": {
        "tech": [
          "Python"
        ]
      }
    },
    {
      "id": "notify.sms_wrk",
      "kind": "service",
      "name": "SMS worker",
      "parent": "notify",
      "attrs": {
        "tech": [
          "Python"
        ]
      }
    },
    {
      "id": "notify.push_wrk",
      "kind": "service",
      "name": "Push worker",
      "parent": "notify",
      "attrs": {
        "tech": [
          "Python"
        ]
      }
    },
    {
      "id": "notify.templates",
      "kind": "datastore",
      "name": "Templates",
      "parent": "notify",
      "attrs": {
        "tech": [
          "PostgreSQL"
        ],
        "owned_by": [
          "api"
        ]
      }
    },
    {
      "id": "notify.prefs",
      "kind": "datastore",
      "name": "User preferences",
      "parent": "notify",
      "attrs": {
        "tech": [
          "PostgreSQL"
        ],
        "owned_by": [
          "api"
        ]
      }
    },
    {
      "id": "notify.sent",
      "kind": "datastore",
      "name": "Delivery log",
      "parent": "notify",
      "attrs": {
        "tech": [
          "ClickHouse"
        ]
      }
    },
    {
      "id": "orders",
      "kind": "external",
      "name": "Orders service",
      "attrs": {
        "description": [
          "an internal caller"
        ]
      }
    },
    {
      "id": "mailer",
      "kind": "external",
      "name": "Email provider"
    },
    {
      "id": "smsgw",
      "kind": "external",
      "name": "SMS gateway"
    },
    {
      "id": "pushgw",
      "kind": "external",
      "name": "Push service"
    }
  ],
  "relations": [
    {
      "from": "api",
      "verb": "reads",
      "to": "prefs",
      "over": "SQL",
      "label": "opt-outs, quiet hours"
    },
    {
      "from": "api",
      "verb": "reads",
      "to": "templates",
      "over": "SQL"
    },
    {
      "from": "api",
      "verb": "publishes",
      "to": "send.email",
      "via": [
        "queue"
      ]
    },
    {
      "from": "api",
      "verb": "publishes",
      "to": "send.sms",
      "via": [
        "queue"
      ]
    },
    {
      "from": "api",
      "verb": "publishes",
      "to": "send.push",
      "via": [
        "queue"
      ]
    },
    {
      "from": "email_wrk",
      "verb": "subscribes",
      "to": "send.email",
      "via": [
        "queue"
      ]
    },
    {
      "from": "sms_wrk",
      "verb": "subscribes",
      "to": "send.sms",
      "via": [
        "queue"
      ]
    },
    {
      "from": "push_wrk",
      "verb": "subscribes",
      "to": "send.push",
      "via": [
        "queue"
      ]
    },
    {
      "from": "email_wrk",
      "verb": "writes",
      "to": "sent",
      "over": "HTTP"
    },
    {
      "from": "sms_wrk",
      "verb": "writes",
      "to": "sent",
      "over": "HTTP"
    },
    {
      "from": "push_wrk",
      "verb": "writes",
      "to": "sent",
      "over": "HTTP"
    },
    {
      "from": "orders",
      "verb": "calls",
      "to": "notify.api",
      "over": "HTTPS",
      "label": "send(user, template, data)"
    },
    {
      "from": "notify.email_wrk",
      "verb": "calls",
      "to": "mailer",
      "over": "HTTPS"
    },
    {
      "from": "notify.sms_wrk",
      "verb": "calls",
      "to": "smsgw",
      "over": "HTTPS"
    },
    {
      "from": "notify.push_wrk",
      "verb": "calls",
      "to": "pushgw",
      "over": "HTTPS"
    }
  ],
  "placements": []
}

# Video upload & playback — upload once, transcode into renditions, serve from a CDN
actor    creator  "Creator"
actor    viewer   "Viewer"
external cdn      "CDN"

system video "Video platform" {
  service   upload     "Upload service"    tech Go
  job       transcode  "Transcoder"        tech "C++ · ffmpeg"
  service   catalog    "Catalog API"       tech Go
  broker    jobs       "Transcode jobs"    { transit  tech SQS }
  topic     video.uploaded
  datastore raw        "Raw uploads"       tech S3   owned_by upload
  datastore renditions "Renditions"        tech S3   owned_by transcode
  datastore meta       "Video metadata"    tech PostgreSQL  owned_by catalog

  upload    writes     raw        over HTTPS   "multipart, resumable"
  upload    publishes  video.uploaded via jobs
  transcode subscribes video.uploaded via jobs
  transcode reads      raw        over HTTPS
  transcode writes     renditions over HTTPS   "1080p · 720p · 480p · HLS"
  transcode writes     meta       over SQL     "ready"
  catalog   reads      meta       over SQL
}

creator calls video.upload  over HTTPS "upload"
viewer  calls video.catalog over HTTPS "browse · play"
viewer  calls cdn           over HTTPS "segments"
cdn     reads video.renditions over HTTPS "origin pull"

env prod "Production" {
  cluster k8s "Kubernetes" nodes 6 cpu 16 mem 64Gi {
    run video.upload    replicas 3 cpu 1 mem 2Gi
    run video.catalog   replicas 3 cpu 0.5 mem 1Gi
    run video.transcode replicas 8 cpu 4 mem 8Gi
  }
}

archcode: "0.2"
objects:
  - id: creator
    kind: actor
    name: Creator
  - id: viewer
    kind: actor
    name: Viewer
  - id: cdn
    kind: external
    name: CDN
  - id: video
    kind: system
    name: "Video platform"
  - id: video.upload
    kind: service
    name: "Upload service"
    parent: video
    attrs:
      tech: [Go]
  - id: video.transcode
    kind: job
    name: Transcoder
    parent: video
    attrs:
      tech: ["C++ · ffmpeg"]
  - id: video.catalog
    kind: service
    name: "Catalog API"
    parent: video
    attrs:
      tech: [Go]
  - id: video.jobs
    kind: broker
    name: "Transcode jobs"
    parent: video
    attrs:
      transit: []
      tech: [SQS]
  - id: video.uploaded
    kind: topic
    parent: video
  - id: video.raw
    kind: datastore
    name: "Raw uploads"
    parent: video
    attrs:
      tech: [S3]
      owned_by: [upload]
  - id: video.renditions
    kind: datastore
    name: Renditions
    parent: video
    attrs:
      tech: [S3]
      owned_by: [transcode]
  - id: video.meta
    kind: datastore
    name: "Video metadata"
    parent: video
    attrs:
      tech: [PostgreSQL]
      owned_by: [catalog]
  - id: prod
    kind: env
    name: Production
  - id: prod.k8s
    kind: cluster
    name: Kubernetes
    parent: prod
    attrs:
      nodes: ["6"]
      cpu: ["16"]
      mem: [64Gi]
relations:
  - from: upload
    verb: writes
    to: raw
    over: HTTPS
    label: "multipart, resumable"
  - from: upload
    verb: publishes
    to: video.uploaded
    via: [jobs]
  - from: transcode
    verb: subscribes
    to: video.uploaded
    via: [jobs]
  - from: transcode
    verb: reads
    to: raw
    over: HTTPS
  - from: transcode
    verb: writes
    to: renditions
    over: HTTPS
    label: "1080p · 720p · 480p · HLS"
  - from: transcode
    verb: writes
    to: meta
    over: SQL
    label: ready
  - from: catalog
    verb: reads
    to: meta
    over: SQL
  - from: creator
    verb: calls
    to: video.upload
    over: HTTPS
    label: upload
  - from: viewer
    verb: calls
    to: video.catalog
    over: HTTPS
    label: "browse · play"
  - from: viewer
    verb: calls
    to: cdn
    over: HTTPS
    label: segments
  - from: cdn
    verb: reads
    to: video.renditions
    over: HTTPS
    label: "origin pull"
placements:
  - host: prod.k8s
    run: video.upload
    attrs:
      replicas: ["3"]
      cpu: ["1"]
      mem: [2Gi]
  - host: prod.k8s
    run: video.catalog
    attrs:
      replicas: ["3"]
      cpu: ["0.5"]
      mem: [1Gi]
  - host: prod.k8s
    run: video.transcode
    attrs:
      replicas: ["8"]
      cpu: ["4"]
      mem: [8Gi]

{
  "archcode": "0.2",
  "objects": [
    {
      "id": "creator",
      "kind": "actor",
      "name": "Creator"
    },
    {
      "id": "viewer",
      "kind": "actor",
      "name": "Viewer"
    },
    {
      "id": "cdn",
      "kind": "external",
      "name": "CDN"
    },
    {
      "id": "video",
      "kind": "system",
      "name": "Video platform"
    },
    {
      "id": "video.upload",
      "kind": "service",
      "name": "Upload service",
      "parent": "video",
      "attrs": {
        "tech": [
          "Go"
        ]
      }
    },
    {
      "id": "video.transcode",
      "kind": "job",
      "name": "Transcoder",
      "parent": "video",
      "attrs": {
        "tech": [
          "C++ · ffmpeg"
        ]
      }
    },
    {
      "id": "video.catalog",
      "kind": "service",
      "name": "Catalog API",
      "parent": "video",
      "attrs": {
        "tech": [
          "Go"
        ]
      }
    },
    {
      "id": "video.jobs",
      "kind": "broker",
      "name": "Transcode jobs",
      "parent": "video",
      "attrs": {
        "transit": [],
        "tech": [
          "SQS"
        ]
      }
    },
    {
      "id": "video.uploaded",
      "kind": "topic",
      "parent": "video"
    },
    {
      "id": "video.raw",
      "kind": "datastore",
      "name": "Raw uploads",
      "parent": "video",
      "attrs": {
        "tech": [
          "S3"
        ],
        "owned_by": [
          "upload"
        ]
      }
    },
    {
      "id": "video.renditions",
      "kind": "datastore",
      "name": "Renditions",
      "parent": "video",
      "attrs": {
        "tech": [
          "S3"
        ],
        "owned_by": [
          "transcode"
        ]
      }
    },
    {
      "id": "video.meta",
      "kind": "datastore",
      "name": "Video metadata",
      "parent": "video",
      "attrs": {
        "tech": [
          "PostgreSQL"
        ],
        "owned_by": [
          "catalog"
        ]
      }
    },
    {
      "id": "prod",
      "kind": "env",
      "name": "Production"
    },
    {
      "id": "prod.k8s",
      "kind": "cluster",
      "name": "Kubernetes",
      "parent": "prod",
      "attrs": {
        "nodes": [
          "6"
        ],
        "cpu": [
          "16"
        ],
        "mem": [
          "64Gi"
        ]
      }
    }
  ],
  "relations": [
    {
      "from": "upload",
      "verb": "writes",
      "to": "raw",
      "over": "HTTPS",
      "label": "multipart, resumable"
    },
    {
      "from": "upload",
      "verb": "publishes",
      "to": "video.uploaded",
      "via": [
        "jobs"
      ]
    },
    {
      "from": "transcode",
      "verb": "subscribes",
      "to": "video.uploaded",
      "via": [
        "jobs"
      ]
    },
    {
      "from": "transcode",
      "verb": "reads",
      "to": "raw",
      "over": "HTTPS"
    },
    {
      "from": "transcode",
      "verb": "writes",
      "to": "renditions",
      "over": "HTTPS",
      "label": "1080p · 720p · 480p · HLS"
    },
    {
      "from": "transcode",
      "verb": "writes",
      "to": "meta",
      "over": "SQL",
      "label": "ready"
    },
    {
      "from": "catalog",
      "verb": "reads",
      "to": "meta",
      "over": "SQL"
    },
    {
      "from": "creator",
      "verb": "calls",
      "to": "video.upload",
      "over": "HTTPS",
      "label": "upload"
    },
    {
      "from": "viewer",
      "verb": "calls",
      "to": "video.catalog",
      "over": "HTTPS",
      "label": "browse · play"
    },
    {
      "from": "viewer",
      "verb": "calls",
      "to": "cdn",
      "over": "HTTPS",
      "label": "segments"
    },
    {
      "from": "cdn",
      "verb": "reads",
      "to": "video.renditions",
      "over": "HTTPS",
      "label": "origin pull"
    }
  ],
  "placements": [
    {
      "host": "prod.k8s",
      "run": "video.upload",
      "attrs": {
        "replicas": [
          "3"
        ],
        "cpu": [
          "1"
        ],
        "mem": [
          "2Gi"
        ]
      }
    },
    {
      "host": "prod.k8s",
      "run": "video.catalog",
      "attrs": {
        "replicas": [
          "3"
        ],
        "cpu": [
          "0.5"
        ],
        "mem": [
          "1Gi"
        ]
      }
    },
    {
      "host": "prod.k8s",
      "run": "video.transcode",
      "attrs": {
        "replicas": [
          "8"
        ],
        "cpu": [
          "4"
        ],
        "mem": [
          "8Gi"
        ]
      }
    }
  ]
}

# Ticket shop — sizing: the figures live beside the services, the resources table is computed from
# them per environment and per moment (`at 2027-06 …`), and a store's growth is projected.
# Open the Resources tab; then change a replica count and watch the totals move.

actor    buyer "Buyer"
external psp   "Payment provider" tech REST

system tickets "Ticket shop" owner @team-tickets availability 24x7 {
  webapp    web       "Web shop"       tech Next.js
  gateway   gw        "API gateway"    tech Envoy { transit }
  service   catalog   "Catalog"        tech Go     cpu 0.5 mem 512Mi
  service   booking   "Booking"        tech Go     cpu 1   mem 1Gi   { capacity rps 800 p99 150ms }
  service   payments  "Payments"       tech Kotlin cpu 1   mem 1Gi
  job       release   "Seat release"   tech Go     description "frees seats held longer than 10 minutes"
  cache     holds     "Seat holds"     tech Redis
  datastore events_db "Events & seats" tech "PostgreSQL 16" owned_by booking  { capacity size 120Gi growth 6Gi/mo }
  datastore orders_db "Orders"         tech "PostgreSQL 16" owned_by payments { capacity size 80Gi  growth 9Gi/mo }
}

buyer            calls  tickets.web       over HTTPS
tickets.web      calls  tickets.catalog   over HTTPS via tickets.gw "browse"
tickets.web      calls  tickets.booking   over HTTPS via tickets.gw "hold a seat"
tickets.web      calls  tickets.payments  over HTTPS via tickets.gw "pay"
tickets.catalog  reads  tickets.events_db over SQL
tickets.booking  writes tickets.events_db over SQL
tickets.booking  writes tickets.holds     over RESP "hold for 10 min"
tickets.payments calls  psp               over HTTPS "authorise"
tickets.payments writes tickets.orders_db over SQL
tickets.payments calls  tickets.booking   over gRPC "confirm the seat"
tickets.release  reads  tickets.holds     over RESP
tickets.release  writes tickets.events_db over SQL

env prod "Production" {
  cluster k8s "Kubernetes" nodes 4 cpu 8 mem 32Gi disk 100Gi {
    run tickets.web      replicas 2 cpu 0.3/1   mem 256Mi/512Mi
    run tickets.gw       replicas 2 cpu 0.5/1   mem 256Mi/512Mi
    run tickets.catalog  replicas 2 cpu 0.5/1   mem 512Mi/1Gi
    run tickets.booking  replicas 3 cpu 1/2     mem 1Gi/2Gi      at 2027-06 replicas 6
    run tickets.payments replicas 2 cpu 1/2     mem 1Gi/2Gi
    run tickets.release  replicas 1 cpu 0.2/0.5 mem 128Mi/256Mi
    agent fluent_bit, node_exporter
  }
  node cache "Redis VMs" count 2 cpu 4 mem 8Gi disk 40Gi {
    run tickets.holds
    agent node_exporter, keepalived
    at 2027-06 count 3
  }
  managed pg "Managed Postgres" {
    run tickets.events_db disk 500Gi
    run tickets.orders_db disk 300Gi
  }
}

env stage "Staging" {
  cluster k8s "Kubernetes" nodes 2 cpu 4 mem 16Gi disk 50Gi {
    run tickets.web, tickets.gw, tickets.catalog, tickets.booking, tickets.payments, tickets.release
    agent fluent_bit
  }
  node one "One VM" cpu 4 mem 8Gi disk 100Gi { run tickets.holds, tickets.events_db, tickets.orders_db  agent node_exporter }
}

archcode: "0.2"
objects:
  - id: buyer
    kind: actor
    name: Buyer
  - id: psp
    kind: external
    name: "Payment provider"
    attrs:
      tech: [REST]
  - id: tickets
    kind: system
    name: "Ticket shop"
    attrs:
      owner: ["@team-tickets"]
      availability: [24x7]
  - id: tickets.web
    kind: webapp
    name: "Web shop"
    parent: tickets
    attrs:
      tech: [Next.js]
  - id: tickets.gw
    kind: gateway
    name: "API gateway"
    parent: tickets
    attrs:
      tech: [Envoy]
      transit: []
  - id: tickets.catalog
    kind: service
    name: Catalog
    parent: tickets
    attrs:
      tech: [Go]
      cpu: ["0.5"]
      mem: [512Mi]
  - id: tickets.booking
    kind: service
    name: Booking
    parent: tickets
    attrs:
      tech: [Go]
      cpu: ["1"]
      mem: [1Gi]
      capacity: [rps, "800", p99, 150ms]
  - id: tickets.payments
    kind: service
    name: Payments
    parent: tickets
    attrs:
      tech: [Kotlin]
      cpu: ["1"]
      mem: [1Gi]
  - id: tickets.release
    kind: job
    name: "Seat release"
    parent: tickets
    attrs:
      tech: [Go]
      description: ["frees seats held longer than 10 minutes"]
  - id: tickets.holds
    kind: cache
    name: "Seat holds"
    parent: tickets
    attrs:
      tech: [Redis]
  - id: tickets.events_db
    kind: datastore
    name: "Events & seats"
    parent: tickets
    attrs:
      tech: ["PostgreSQL 16"]
      owned_by: [booking]
      capacity: [size, 120Gi, growth, 6Gi/mo]
  - id: tickets.orders_db
    kind: datastore
    name: Orders
    parent: tickets
    attrs:
      tech: ["PostgreSQL 16"]
      owned_by: [payments]
      capacity: [size, 80Gi, growth, 9Gi/mo]
  - id: prod
    kind: env
    name: Production
  - id: prod.k8s
    kind: cluster
    name: Kubernetes
    parent: prod
    attrs:
      nodes: ["4"]
      cpu: ["8"]
      mem: [32Gi]
      disk: [100Gi]
      agent: [fluent_bit, node_exporter]
  - id: prod.cache
    kind: node
    name: "Redis VMs"
    parent: prod
    attrs:
      count: ["2"]
      cpu: ["4"]
      mem: [8Gi]
      disk: [40Gi]
      agent: [node_exporter, keepalived]
    timeline:
      - at: 2027-06
        attrs:
          count: ["3"]
  - id: prod.pg
    kind: managed
    name: "Managed Postgres"
    parent: prod
  - id: stage
    kind: env
    name: Staging
  - id: stage.k8s
    kind: cluster
    name: Kubernetes
    parent: stage
    attrs:
      nodes: ["2"]
      cpu: ["4"]
      mem: [16Gi]
      disk: [50Gi]
      agent: [fluent_bit]
  - id: stage.one
    kind: node
    name: "One VM"
    parent: stage
    attrs:
      cpu: ["4"]
      mem: [8Gi]
      disk: [100Gi]
      agent: [node_exporter]
relations:
  - from: buyer
    verb: calls
    to: tickets.web
    over: HTTPS
  - from: tickets.web
    verb: calls
    to: tickets.catalog
    over: HTTPS
    via: [tickets.gw]
    label: browse
  - from: tickets.web
    verb: calls
    to: tickets.booking
    over: HTTPS
    via: [tickets.gw]
    label: "hold a seat"
  - from: tickets.web
    verb: calls
    to: tickets.payments
    over: HTTPS
    via: [tickets.gw]
    label: pay
  - from: tickets.catalog
    verb: reads
    to: tickets.events_db
    over: SQL
  - from: tickets.booking
    verb: writes
    to: tickets.events_db
    over: SQL
  - from: tickets.booking
    verb: writes
    to: tickets.holds
    over: RESP
    label: "hold for 10 min"
  - from: tickets.payments
    verb: calls
    to: psp
    over: HTTPS
    label: authorise
  - from: tickets.payments
    verb: writes
    to: tickets.orders_db
    over: SQL
  - from: tickets.payments
    verb: calls
    to: tickets.booking
    over: gRPC
    label: "confirm the seat"
  - from: tickets.release
    verb: reads
    to: tickets.holds
    over: RESP
  - from: tickets.release
    verb: writes
    to: tickets.events_db
    over: SQL
placements:
  - host: prod.k8s
    run: tickets.web
    attrs:
      replicas: ["2"]
      cpu: [0.3/1]
      mem: [256Mi/512Mi]
  - host: prod.k8s
    run: tickets.gw
    attrs:
      replicas: ["2"]
      cpu: [0.5/1]
      mem: [256Mi/512Mi]
  - host: prod.k8s
    run: tickets.catalog
    attrs:
      replicas: ["2"]
      cpu: [0.5/1]
      mem: [512Mi/1Gi]
  - host: prod.k8s
    run: tickets.booking
    attrs:
      replicas: ["3"]
      cpu: [1/2]
      mem: [1Gi/2Gi]
    timeline:
      - at: 2027-06
        attrs:
          replicas: ["6"]
  - host: prod.k8s
    run: tickets.payments
    attrs:
      replicas: ["2"]
      cpu: [1/2]
      mem: [1Gi/2Gi]
  - host: prod.k8s
    run: tickets.release
    attrs:
      replicas: ["1"]
      cpu: [0.2/0.5]
      mem: [128Mi/256Mi]
  - host: prod.cache
    run: tickets.holds
  - host: prod.pg
    run: tickets.events_db
    attrs:
      disk: [500Gi]
  - host: prod.pg
    run: tickets.orders_db
    attrs:
      disk: [300Gi]
  - host: stage.k8s
    run: tickets.web
  - host: stage.k8s
    run: tickets.gw
  - host: stage.k8s
    run: tickets.catalog
  - host: stage.k8s
    run: tickets.booking
  - host: stage.k8s
    run: tickets.payments
  - host: stage.k8s
    run: tickets.release
  - host: stage.one
    run: tickets.holds
  - host: stage.one
    run: tickets.events_db
  - host: stage.one
    run: tickets.orders_db

{
  "archcode": "0.2",
  "objects": [
    {
      "id": "buyer",
      "kind": "actor",
      "name": "Buyer"
    },
    {
      "id": "psp",
      "kind": "external",
      "name": "Payment provider",
      "attrs": {
        "tech": [
          "REST"
        ]
      }
    },
    {
      "id": "tickets",
      "kind": "system",
      "name": "Ticket shop",
      "attrs": {
        "owner": [
          "@team-tickets"
        ],
        "availability": [
          "24x7"
        ]
      }
    },
    {
      "id": "tickets.web",
      "kind": "webapp",
      "name": "Web shop",
      "parent": "tickets",
      "attrs": {
        "tech": [
          "Next.js"
        ]
      }
    },
    {
      "id": "tickets.gw",
      "kind": "gateway",
      "name": "API gateway",
      "parent": "tickets",
      "attrs": {
        "tech": [
          "Envoy"
        ],
        "transit": []
      }
    },
    {
      "id": "tickets.catalog",
      "kind": "service",
      "name": "Catalog",
      "parent": "tickets",
      "attrs": {
        "tech": [
          "Go"
        ],
        "cpu": [
          "0.5"
        ],
        "mem": [
          "512Mi"
        ]
      }
    },
    {
      "id": "tickets.booking",
      "kind": "service",
      "name": "Booking",
      "parent": "tickets",
      "attrs": {
        "tech": [
          "Go"
        ],
        "cpu": [
          "1"
        ],
        "mem": [
          "1Gi"
        ],
        "capacity": [
          "rps",
          "800",
          "p99",
          "150ms"
        ]
      }
    },
    {
      "id": "tickets.payments",
      "kind": "service",
      "name": "Payments",
      "parent": "tickets",
      "attrs": {
        "tech": [
          "Kotlin"
        ],
        "cpu": [
          "1"
        ],
        "mem": [
          "1Gi"
        ]
      }
    },
    {
      "id": "tickets.release",
      "kind": "job",
      "name": "Seat release",
      "parent": "tickets",
      "attrs": {
        "tech": [
          "Go"
        ],
        "description": [
          "frees seats held longer than 10 minutes"
        ]
      }
    },
    {
      "id": "tickets.holds",
      "kind": "cache",
      "name": "Seat holds",
      "parent": "tickets",
      "attrs": {
        "tech": [
          "Redis"
        ]
      }
    },
    {
      "id": "tickets.events_db",
      "kind": "datastore",
      "name": "Events & seats",
      "parent": "tickets",
      "attrs": {
        "tech": [
          "PostgreSQL 16"
        ],
        "owned_by": [
          "booking"
        ],
        "capacity": [
          "size",
          "120Gi",
          "growth",
          "6Gi/mo"
        ]
      }
    },
    {
      "id": "tickets.orders_db",
      "kind": "datastore",
      "name": "Orders",
      "parent": "tickets",
      "attrs": {
        "tech": [
          "PostgreSQL 16"
        ],
        "owned_by": [
          "payments"
        ],
        "capacity": [
          "size",
          "80Gi",
          "growth",
          "9Gi/mo"
        ]
      }
    },
    {
      "id": "prod",
      "kind": "env",
      "name": "Production"
    },
    {
      "id": "prod.k8s",
      "kind": "cluster",
      "name": "Kubernetes",
      "parent": "prod",
      "attrs": {
        "nodes": [
          "4"
        ],
        "cpu": [
          "8"
        ],
        "mem": [
          "32Gi"
        ],
        "disk": [
          "100Gi"
        ],
        "agent": [
          "fluent_bit",
          "node_exporter"
        ]
      }
    },
    {
      "id": "prod.cache",
      "kind": "node",
      "name": "Redis VMs",
      "parent": "prod",
      "attrs": {
        "count": [
          "2"
        ],
        "cpu": [
          "4"
        ],
        "mem": [
          "8Gi"
        ],
        "disk": [
          "40Gi"
        ],
        "agent": [
          "node_exporter",
          "keepalived"
        ]
      },
      "timeline": [
        {
          "at": "2027-06",
          "attrs": {
            "count": [
              "3"
            ]
          }
        }
      ]
    },
    {
      "id": "prod.pg",
      "kind": "managed",
      "name": "Managed Postgres",
      "parent": "prod"
    },
    {
      "id": "stage",
      "kind": "env",
      "name": "Staging"
    },
    {
      "id": "stage.k8s",
      "kind": "cluster",
      "name": "Kubernetes",
      "parent": "stage",
      "attrs": {
        "nodes": [
          "2"
        ],
        "cpu": [
          "4"
        ],
        "mem": [
          "16Gi"
        ],
        "disk": [
          "50Gi"
        ],
        "agent": [
          "fluent_bit"
        ]
      }
    },
    {
      "id": "stage.one",
      "kind": "node",
      "name": "One VM",
      "parent": "stage",
      "attrs": {
        "cpu": [
          "4"
        ],
        "mem": [
          "8Gi"
        ],
        "disk": [
          "100Gi"
        ],
        "agent": [
          "node_exporter"
        ]
      }
    }
  ],
  "relations": [
    {
      "from": "buyer",
      "verb": "calls",
      "to": "tickets.web",
      "over": "HTTPS"
    },
    {
      "from": "tickets.web",
      "verb": "calls",
      "to": "tickets.catalog",
      "over": "HTTPS",
      "via": [
        "tickets.gw"
      ],
      "label": "browse"
    },
    {
      "from": "tickets.web",
      "verb": "calls",
      "to": "tickets.booking",
      "over": "HTTPS",
      "via": [
        "tickets.gw"
      ],
      "label": "hold a seat"
    },
    {
      "from": "tickets.web",
      "verb": "calls",
      "to": "tickets.payments",
      "over": "HTTPS",
      "via": [
        "tickets.gw"
      ],
      "label": "pay"
    },
    {
      "from": "tickets.catalog",
      "verb": "reads",
      "to": "tickets.events_db",
      "over": "SQL"
    },
    {
      "from": "tickets.booking",
      "verb": "writes",
      "to": "tickets.events_db",
      "over": "SQL"
    },
    {
      "from": "tickets.booking",
      "verb": "writes",
      "to": "tickets.holds",
      "over": "RESP",
      "label": "hold for 10 min"
    },
    {
      "from": "tickets.payments",
      "verb": "calls",
      "to": "psp",
      "over": "HTTPS",
      "label": "authorise"
    },
    {
      "from": "tickets.payments",
      "verb": "writes",
      "to": "tickets.orders_db",
      "over": "SQL"
    },
    {
      "from": "tickets.payments",
      "verb": "calls",
      "to": "tickets.booking",
      "over": "gRPC",
      "label": "confirm the seat"
    },
    {
      "from": "tickets.release",
      "verb": "reads",
      "to": "tickets.holds",
      "over": "RESP"
    },
    {
      "from": "tickets.release",
      "verb": "writes",
      "to": "tickets.events_db",
      "over": "SQL"
    }
  ],
  "placements": [
    {
      "host": "prod.k8s",
      "run": "tickets.web",
      "attrs": {
        "replicas": [
          "2"
        ],
        "cpu": [
          "0.3/1"
        ],
        "mem": [
          "256Mi/512Mi"
        ]
      }
    },
    {
      "host": "prod.k8s",
      "run": "tickets.gw",
      "attrs": {
        "replicas": [
          "2"
        ],
        "cpu": [
          "0.5/1"
        ],
        "mem": [
          "256Mi/512Mi"
        ]
      }
    },
    {
      "host": "prod.k8s",
      "run": "tickets.catalog",
      "attrs": {
        "replicas": [
          "2"
        ],
        "cpu": [
          "0.5/1"
        ],
        "mem": [
          "512Mi/1Gi"
        ]
      }
    },
    {
      "host": "prod.k8s",
      "run": "tickets.booking",
      "attrs": {
        "replicas": [
          "3"
        ],
        "cpu": [
          "1/2"
        ],
        "mem": [
          "1Gi/2Gi"
        ]
      },
      "timeline": [
        {
          "at": "2027-06",
          "attrs": {
            "replicas": [
              "6"
            ]
          }
        }
      ]
    },
    {
      "host": "prod.k8s",
      "run": "tickets.payments",
      "attrs": {
        "replicas": [
          "2"
        ],
        "cpu": [
          "1/2"
        ],
        "mem": [
          "1Gi/2Gi"
        ]
      }
    },
    {
      "host": "prod.k8s",
      "run": "tickets.release",
      "attrs": {
        "replicas": [
          "1"
        ],
        "cpu": [
          "0.2/0.5"
        ],
        "mem": [
          "128Mi/256Mi"
        ]
      }
    },
    {
      "host": "prod.cache",
      "run": "tickets.holds"
    },
    {
      "host": "prod.pg",
      "run": "tickets.events_db",
      "attrs": {
        "disk": [
          "500Gi"
        ]
      }
    },
    {
      "host": "prod.pg",
      "run": "tickets.orders_db",
      "attrs": {
        "disk": [
          "300Gi"
        ]
      }
    },
    {
      "host": "stage.k8s",
      "run": "tickets.web"
    },
    {
      "host": "stage.k8s",
      "run": "tickets.gw"
    },
    {
      "host": "stage.k8s",
      "run": "tickets.catalog"
    },
    {
      "host": "stage.k8s",
      "run": "tickets.booking"
    },
    {
      "host": "stage.k8s",
      "run": "tickets.payments"
    },
    {
      "host": "stage.k8s",
      "run": "tickets.release"
    },
    {
      "host": "stage.one",
      "run": "tickets.holds"
    },
    {
      "host": "stage.one",
      "run": "tickets.events_db"
    },
    {
      "host": "stage.one",
      "run": "tickets.orders_db"
    }
  ]
}

# Parcel tracking — the infrastructure layer: a gateway in front, a broker between, both `transit`.
# The logical picture folds them into the arrows ("via gw", "via bus"); the Infrastructure lens
# opens them as cards with every hop. Same file, one switch, nothing redeclared.

actor    customer "Customer"
actor    courier  "Courier"           description "scans parcels from the app"
external sms      "SMS provider"      tech REST

system track "Parcel tracking" owner @team-track {
  webapp    site     "Tracking site"    tech React
  webapp    app      "Courier app"      tech "React Native"
  gateway   gw       "Edge gateway"     tech Kong    { transit }
  service   parcels  "Parcels"          tech Go
  service   scans    "Scan intake"      tech Go
  service   notify   "Notifications"    tech Python
  broker    bus      "Event bus"        tech Kafka   { transit }
  datastore parcels_db "Parcels"        tech "PostgreSQL 16" owned_by parcels
  cache     eta      "ETA cache"        tech Redis
  topic     parcel.scanned
  topic     parcel.delivered
}

customer      calls      track.site     over HTTPS
courier       calls      track.app      over HTTPS
track.site    calls      track.parcels  over HTTPS via track.gw "where is my parcel"
track.app     calls      track.scans    over HTTPS via track.gw "scan"
track.parcels reads      track.parcels_db over SQL
track.parcels reads      track.eta      over RESP
track.scans   writes     track.parcels_db over SQL
track.scans   publishes  parcel.scanned   via track.bus
track.scans   publishes  parcel.delivered via track.bus
track.parcels subscribes parcel.scanned   via track.bus "recompute the ETA"
track.parcels writes     track.eta      over RESP
track.notify  subscribes parcel.delivered via track.bus
track.notify  calls      sms            over HTTPS "delivered"

archcode: "0.2"
objects:
  - id: customer
    kind: actor
    name: Customer
  - id: courier
    kind: actor
    name: Courier
    attrs:
      description: ["scans parcels from the app"]
  - id: sms
    kind: external
    name: "SMS provider"
    attrs:
      tech: [REST]
  - id: track
    kind: system
    name: "Parcel tracking"
    attrs:
      owner: ["@team-track"]
  - id: track.site
    kind: webapp
    name: "Tracking site"
    parent: track
    attrs:
      tech: [React]
  - id: track.app
    kind: webapp
    name: "Courier app"
    parent: track
    attrs:
      tech: ["React Native"]
  - id: track.gw
    kind: gateway
    name: "Edge gateway"
    parent: track
    attrs:
      tech: [Kong]
      transit: []
  - id: track.parcels
    kind: service
    name: Parcels
    parent: track
    attrs:
      tech: [Go]
  - id: track.scans
    kind: service
    name: "Scan intake"
    parent: track
    attrs:
      tech: [Go]
  - id: track.notify
    kind: service
    name: Notifications
    parent: track
    attrs:
      tech: [Python]
  - id: track.bus
    kind: broker
    name: "Event bus"
    parent: track
    attrs:
      tech: [Kafka]
      transit: []
  - id: track.parcels_db
    kind: datastore
    name: Parcels
    parent: track
    attrs:
      tech: ["PostgreSQL 16"]
      owned_by: [parcels]
  - id: track.eta
    kind: cache
    name: "ETA cache"
    parent: track
    attrs:
      tech: [Redis]
  - id: parcel.scanned
    kind: topic
    parent: track
  - id: parcel.delivered
    kind: topic
    parent: track
relations:
  - from: customer
    verb: calls
    to: track.site
    over: HTTPS
  - from: courier
    verb: calls
    to: track.app
    over: HTTPS
  - from: track.site
    verb: calls
    to: track.parcels
    over: HTTPS
    via: [track.gw]
    label: "where is my parcel"
  - from: track.app
    verb: calls
    to: track.scans
    over: HTTPS
    via: [track.gw]
    label: scan
  - from: track.parcels
    verb: reads
    to: track.parcels_db
    over: SQL
  - from: track.parcels
    verb: reads
    to: track.eta
    over: RESP
  - from: track.scans
    verb: writes
    to: track.parcels_db
    over: SQL
  - from: track.scans
    verb: publishes
    to: parcel.scanned
    via: [track.bus]
  - from: track.scans
    verb: publishes
    to: parcel.delivered
    via: [track.bus]
  - from: track.parcels
    verb: subscribes
    to: parcel.scanned
    via: [track.bus]
    label: "recompute the ETA"
  - from: track.parcels
    verb: writes
    to: track.eta
    over: RESP
  - from: track.notify
    verb: subscribes
    to: parcel.delivered
    via: [track.bus]
  - from: track.notify
    verb: calls
    to: sms
    over: HTTPS
    label: delivered
placements: []

{
  "archcode": "0.2",
  "objects": [
    {
      "id": "customer",
      "kind": "actor",
      "name": "Customer"
    },
    {
      "id": "courier",
      "kind": "actor",
      "name": "Courier",
      "attrs": {
        "description": [
          "scans parcels from the app"
        ]
      }
    },
    {
      "id": "sms",
      "kind": "external",
      "name": "SMS provider",
      "attrs": {
        "tech": [
          "REST"
        ]
      }
    },
    {
      "id": "track",
      "kind": "system",
      "name": "Parcel tracking",
      "attrs": {
        "owner": [
          "@team-track"
        ]
      }
    },
    {
      "id": "track.site",
      "kind": "webapp",
      "name": "Tracking site",
      "parent": "track",
      "attrs": {
        "tech": [
          "React"
        ]
      }
    },
    {
      "id": "track.app",
      "kind": "webapp",
      "name": "Courier app",
      "parent": "track",
      "attrs": {
        "tech": [
          "React Native"
        ]
      }
    },
    {
      "id": "track.gw",
      "kind": "gateway",
      "name": "Edge gateway",
      "parent": "track",
      "attrs": {
        "tech": [
          "Kong"
        ],
        "transit": []
      }
    },
    {
      "id": "track.parcels",
      "kind": "service",
      "name": "Parcels",
      "parent": "track",
      "attrs": {
        "tech": [
          "Go"
        ]
      }
    },
    {
      "id": "track.scans",
      "kind": "service",
      "name": "Scan intake",
      "parent": "track",
      "attrs": {
        "tech": [
          "Go"
        ]
      }
    },
    {
      "id": "track.notify",
      "kind": "service",
      "name": "Notifications",
      "parent": "track",
      "attrs": {
        "tech": [
          "Python"
        ]
      }
    },
    {
      "id": "track.bus",
      "kind": "broker",
      "name": "Event bus",
      "parent": "track",
      "attrs": {
        "tech": [
          "Kafka"
        ],
        "transit": []
      }
    },
    {
      "id": "track.parcels_db",
      "kind": "datastore",
      "name": "Parcels",
      "parent": "track",
      "attrs": {
        "tech": [
          "PostgreSQL 16"
        ],
        "owned_by": [
          "parcels"
        ]
      }
    },
    {
      "id": "track.eta",
      "kind": "cache",
      "name": "ETA cache",
      "parent": "track",
      "attrs": {
        "tech": [
          "Redis"
        ]
      }
    },
    {
      "id": "parcel.scanned",
      "kind": "topic",
      "parent": "track"
    },
    {
      "id": "parcel.delivered",
      "kind": "topic",
      "parent": "track"
    }
  ],
  "relations": [
    {
      "from": "customer",
      "verb": "calls",
      "to": "track.site",
      "over": "HTTPS"
    },
    {
      "from": "courier",
      "verb": "calls",
      "to": "track.app",
      "over": "HTTPS"
    },
    {
      "from": "track.site",
      "verb": "calls",
      "to": "track.parcels",
      "over": "HTTPS",
      "via": [
        "track.gw"
      ],
      "label": "where is my parcel"
    },
    {
      "from": "track.app",
      "verb": "calls",
      "to": "track.scans",
      "over": "HTTPS",
      "via": [
        "track.gw"
      ],
      "label": "scan"
    },
    {
      "from": "track.parcels",
      "verb": "reads",
      "to": "track.parcels_db",
      "over": "SQL"
    },
    {
      "from": "track.parcels",
      "verb": "reads",
      "to": "track.eta",
      "over": "RESP"
    },
    {
      "from": "track.scans",
      "verb": "writes",
      "to": "track.parcels_db",
      "over": "SQL"
    },
    {
      "from": "track.scans",
      "verb": "publishes",
      "to": "parcel.scanned",
      "via": [
        "track.bus"
      ]
    },
    {
      "from": "track.scans",
      "verb": "publishes",
      "to": "parcel.delivered",
      "via": [
        "track.bus"
      ]
    },
    {
      "from": "track.parcels",
      "verb": "subscribes",
      "to": "parcel.scanned",
      "via": [
        "track.bus"
      ],
      "label": "recompute the ETA"
    },
    {
      "from": "track.parcels",
      "verb": "writes",
      "to": "track.eta",
      "over": "RESP"
    },
    {
      "from": "track.notify",
      "verb": "subscribes",
      "to": "parcel.delivered",
      "via": [
        "track.bus"
      ]
    },
    {
      "from": "track.notify",
      "verb": "calls",
      "to": "sms",
      "over": "HTTPS",
      "label": "delivered"
    }
  ],
  "placements": []
}

# Inside one service — C3: a container opened to its components. `payments` is a card on the
# system picture; expand it and the components appear inside, fold it and they go back.
# Everything around it stays exactly where it was.

actor    customer "Customer"
external psp      "Payment provider" tech REST
external ledger   "General ledger"   tech SAP

system shop "Web shop" owner @team-shop {
  webapp    web      "Storefront"   tech Next.js
  service   orders   "Orders"       tech Go
  service   payments "Payments"     tech Kotlin {
    component api       "Payments API"        tech "Spring Web"     description "REST controllers"
    component flow      "Payment flow"        tech "Spring"         description "authorise · capture · refund"
    component psp_client "PSP client"         tech "WebClient"
    component outbox    "Outbox"              tech "Spring Data"    description "events written with the transaction"
    component repo      "Payments repository" tech "Spring Data JDBC"
    api        calls  flow
    flow       calls  psp_client
    flow       calls  repo
    flow       calls  outbox
  }
  service   invoicing "Invoicing"    tech Python
  broker    bus       "Event bus"    tech Kafka { transit }
  datastore payments_db "Payments"   tech "PostgreSQL 16" owned_by payments
  datastore orders_db   "Orders"     tech "PostgreSQL 16" owned_by orders
  topic     payment.captured
}

customer         calls      shop.web           over HTTPS
shop.web         calls      shop.orders        over HTTPS "checkout"
shop.orders      writes     shop.orders_db     over SQL
shop.orders      calls      shop.payments.api  over gRPC "authorise · capture"
shop.payments.psp_client calls psp             over HTTPS
shop.payments.repo writes  shop.payments_db    over SQL
shop.payments.outbox publishes payment.captured via shop.bus
shop.invoicing   subscribes payment.captured   via shop.bus
shop.invoicing   calls      ledger             over HTTPS "post the invoice"

archcode: "0.2"
objects:
  - id: customer
    kind: actor
    name: Customer
  - id: psp
    kind: external
    name: "Payment provider"
    attrs:
      tech: [REST]
  - id: ledger
    kind: external
    name: "General ledger"
    attrs:
      tech: [SAP]
  - id: shop
    kind: system
    name: "Web shop"
    attrs:
      owner: ["@team-shop"]
  - id: shop.web
    kind: webapp
    name: Storefront
    parent: shop
    attrs:
      tech: [Next.js]
  - id: shop.orders
    kind: service
    name: Orders
    parent: shop
    attrs:
      tech: [Go]
  - id: shop.payments
    kind: service
    name: Payments
    parent: shop
    attrs:
      tech: [Kotlin]
  - id: shop.payments.api
    kind: component
    name: "Payments API"
    parent: shop.payments
    attrs:
      tech: ["Spring Web"]
      description: ["REST controllers"]
  - id: shop.payments.flow
    kind: component
    name: "Payment flow"
    parent: shop.payments
    attrs:
      tech: [Spring]
      description: ["authorise · capture · refund"]
  - id: shop.payments.psp_client
    kind: component
    name: "PSP client"
    parent: shop.payments
    attrs:
      tech: [WebClient]
  - id: shop.payments.outbox
    kind: component
    name: Outbox
    parent: shop.payments
    attrs:
      tech: ["Spring Data"]
      description: ["events written with the transaction"]
  - id: shop.payments.repo
    kind: component
    name: "Payments repository"
    parent: shop.payments
    attrs:
      tech: ["Spring Data JDBC"]
  - id: shop.invoicing
    kind: service
    name: Invoicing
    parent: shop
    attrs:
      tech: [Python]
  - id: shop.bus
    kind: broker
    name: "Event bus"
    parent: shop
    attrs:
      tech: [Kafka]
      transit: []
  - id: shop.payments_db
    kind: datastore
    name: Payments
    parent: shop
    attrs:
      tech: ["PostgreSQL 16"]
      owned_by: [payments]
  - id: shop.orders_db
    kind: datastore
    name: Orders
    parent: shop
    attrs:
      tech: ["PostgreSQL 16"]
      owned_by: [orders]
  - id: payment.captured
    kind: topic
    parent: shop
relations:
  - from: api
    verb: calls
    to: flow
  - from: flow
    verb: calls
    to: psp_client
  - from: flow
    verb: calls
    to: repo
  - from: flow
    verb: calls
    to: outbox
  - from: customer
    verb: calls
    to: shop.web
    over: HTTPS
  - from: shop.web
    verb: calls
    to: shop.orders
    over: HTTPS
    label: checkout
  - from: shop.orders
    verb: writes
    to: shop.orders_db
    over: SQL
  - from: shop.orders
    verb: calls
    to: shop.payments.api
    over: gRPC
    label: "authorise · capture"
  - from: shop.payments.psp_client
    verb: calls
    to: psp
    over: HTTPS
  - from: shop.payments.repo
    verb: writes
    to: shop.payments_db
    over: SQL
  - from: shop.payments.outbox
    verb: publishes
    to: payment.captured
    via: [shop.bus]
  - from: shop.invoicing
    verb: subscribes
    to: payment.captured
    via: [shop.bus]
  - from: shop.invoicing
    verb: calls
    to: ledger
    over: HTTPS
    label: "post the invoice"
placements: []

{
  "archcode": "0.2",
  "objects": [
    {
      "id": "customer",
      "kind": "actor",
      "name": "Customer"
    },
    {
      "id": "psp",
      "kind": "external",
      "name": "Payment provider",
      "attrs": {
        "tech": [
          "REST"
        ]
      }
    },
    {
      "id": "ledger",
      "kind": "external",
      "name": "General ledger",
      "attrs": {
        "tech": [
          "SAP"
        ]
      }
    },
    {
      "id": "shop",
      "kind": "system",
      "name": "Web shop",
      "attrs": {
        "owner": [
          "@team-shop"
        ]
      }
    },
    {
      "id": "shop.web",
      "kind": "webapp",
      "name": "Storefront",
      "parent": "shop",
      "attrs": {
        "tech": [
          "Next.js"
        ]
      }
    },
    {
      "id": "shop.orders",
      "kind": "service",
      "name": "Orders",
      "parent": "shop",
      "attrs": {
        "tech": [
          "Go"
        ]
      }
    },
    {
      "id": "shop.payments",
      "kind": "service",
      "name": "Payments",
      "parent": "shop",
      "attrs": {
        "tech": [
          "Kotlin"
        ]
      }
    },
    {
      "id": "shop.payments.api",
      "kind": "component",
      "name": "Payments API",
      "parent": "shop.payments",
      "attrs": {
        "tech": [
          "Spring Web"
        ],
        "description": [
          "REST controllers"
        ]
      }
    },
    {
      "id": "shop.payments.flow",
      "kind": "component",
      "name": "Payment flow",
      "parent": "shop.payments",
      "attrs": {
        "tech": [
          "Spring"
        ],
        "description": [
          "authorise · capture · refund"
        ]
      }
    },
    {
      "id": "shop.payments.psp_client",
      "kind": "component",
      "name": "PSP client",
      "parent": "shop.payments",
      "attrs": {
        "tech": [
          "WebClient"
        ]
      }
    },
    {
      "id": "shop.payments.outbox",
      "kind": "component",
      "name": "Outbox",
      "parent": "shop.payments",
      "attrs": {
        "tech": [
          "Spring Data"
        ],
        "description": [
          "events written with the transaction"
        ]
      }
    },
    {
      "id": "shop.payments.repo",
      "kind": "component",
      "name": "Payments repository",
      "parent": "shop.payments",
      "attrs": {
        "tech": [
          "Spring Data JDBC"
        ]
      }
    },
    {
      "id": "shop.invoicing",
      "kind": "service",
      "name": "Invoicing",
      "parent": "shop",
      "attrs": {
        "tech": [
          "Python"
        ]
      }
    },
    {
      "id": "shop.bus",
      "kind": "broker",
      "name": "Event bus",
      "parent": "shop",
      "attrs": {
        "tech": [
          "Kafka"
        ],
        "transit": []
      }
    },
    {
      "id": "shop.payments_db",
      "kind": "datastore",
      "name": "Payments",
      "parent": "shop",
      "attrs": {
        "tech": [
          "PostgreSQL 16"
        ],
        "owned_by": [
          "payments"
        ]
      }
    },
    {
      "id": "shop.orders_db",
      "kind": "datastore",
      "name": "Orders",
      "parent": "shop",
      "attrs": {
        "tech": [
          "PostgreSQL 16"
        ],
        "owned_by": [
          "orders"
        ]
      }
    },
    {
      "id": "payment.captured",
      "kind": "topic",
      "parent": "shop"
    }
  ],
  "relations": [
    {
      "from": "api",
      "verb": "calls",
      "to": "flow"
    },
    {
      "from": "flow",
      "verb": "calls",
      "to": "psp_client"
    },
    {
      "from": "flow",
      "verb": "calls",
      "to": "repo"
    },
    {
      "from": "flow",
      "verb": "calls",
      "to": "outbox"
    },
    {
      "from": "customer",
      "verb": "calls",
      "to": "shop.web",
      "over": "HTTPS"
    },
    {
      "from": "shop.web",
      "verb": "calls",
      "to": "shop.orders",
      "over": "HTTPS",
      "label": "checkout"
    },
    {
      "from": "shop.orders",
      "verb": "writes",
      "to": "shop.orders_db",
      "over": "SQL"
    },
    {
      "from": "shop.orders",
      "verb": "calls",
      "to": "shop.payments.api",
      "over": "gRPC",
      "label": "authorise · capture"
    },
    {
      "from": "shop.payments.psp_client",
      "verb": "calls",
      "to": "psp",
      "over": "HTTPS"
    },
    {
      "from": "shop.payments.repo",
      "verb": "writes",
      "to": "shop.payments_db",
      "over": "SQL"
    },
    {
      "from": "shop.payments.outbox",
      "verb": "publishes",
      "to": "payment.captured",
      "via": [
        "shop.bus"
      ]
    },
    {
      "from": "shop.invoicing",
      "verb": "subscribes",
      "to": "payment.captured",
      "via": [
        "shop.bus"
      ]
    },
    {
      "from": "shop.invoicing",
      "verb": "calls",
      "to": "ledger",
      "over": "HTTPS",
      "label": "post the invoice"
    }
  ],
  "placements": []
}